How Many Keywords do Searchers Use?

Percentage of U.S. clicks by number of keywords
Subject	October 2009	November 2009	Month-over-month percentage change
One word	24.03%	24.13%	0%
Two words	23.13%	23.14%	0%
Three words	20.53%	20.37%	-1%
four words	13.83%	13.84%	0%
Five words	8.13%	8.13%	0%
Six words	4.42%	4.43%	0%
Seven words	2.43%	2.43%	0%
Eight or more words	3.49%	3.54%	1%
Note: Data is based on four-week rolling periods (ending Nov. 28, 2009, and Oct. 31, 2009) from the Hitwise sample of 10 million U.S. Internet users.

It seems one to three keywords still rules search. Typically, keywords become longtail as they increase in number.